tl;dw: Growing grains in order to make beer is why nomads settled down and began farming in Mesopotamia which led to the development of civilization and culture...then the rest gets foggy because my roommate and I were getting too civilized.

Also drinking water was dangerous because of lack of bacteria control. Brewing beer was a a way to get calories as well as consume liquid safely. Beer was used as a currency in many places. Your daily wage was bread and beer, and how much you got was determined by your place in society.